Shared Flashcard Set

Details

747 APU
updated 2/21/15
17
Aviation
Professional
10/19/2012

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Cards

Term
What does the ON position on the APU selector do?
Definition
Opens APU fuel valve and inlet door
Arms APU bleed air isolation valve
Activates DC or two AC pumps
Term
What does the OFF position on the APU selector do?
Definition
Closes APU bleed air isolation valve
Initiates normal shutdown
Resets auto shutdown fault logic (except for bleed leak)
Term
When does the EICAS memo APU RUNNING display?
Definition
APU selector ON
N1 RPM > 95%
Term
What APU information is provided on the APU Status page?
Definition
EGT, N1, N2, oil quantity
Term
What does RF or LO mean on the APU EICAS page?
Definition
Refill or low oil
Term
Where does the APU controller receive power?
Definition
Primary: APU battery
Standby: Main battery
Term
What provides power to the APU starter?
Definition
When Utility Bus 4 is powered, DC electric starter through TR
or
24 volt APU battery
Term
What APU components are powered by the APU and Main batteries?
Definition
APU:
Inlet door, APU controller, DC fuel pump, APU fire detection

Main: APU fire extinguisher, APU fuel valve, Stby power for APU controller
Term
Which pumps operate the APU? Where are they located?
Definition
Two AC or one DC pump

Main Tank 2: DC pump and one AC pump
Main Tank 3: second AC pump
Term
What are the APU start sequence limits when using the TR?
Definition
Between 1st and 2nd start: 1 min
2 - 3: 10 min
3 - 4: 75 min
Term
What are the APU start sequence limits when using battery power?
Definition
Between 1st and 2nd: 1 min
2 - 3: 1 min
3 - 4: 75 min
Term
What happens if the TR overheats during APU start?
Definition
Start power is transferred to the battery and the start continues on battery power
Any further TR start attempts are inhibited
Term
How does a TR failure affect APU starting?
Definition
Does not automatically switch to APU battery
Switch Start Source to BATTERY
(except for overheat)
Term
Describe the APU shutdown sequence
Definition
APU selector to OFF
Bleed air valve closes
60 second cool down
APU fuel valve closes
20% N1, Inlet door closes
After 2 min, shutdown is complete (fire detection capability)
Term
What causes an APU
auto-shutdown?
Definition
Limit is exceeded
Fire is detected
Battery switch turned OFF during shutdown sequence
Term
What happens if the battery switch is placed to OFF prior to completion of the cool down period?
Definition
APU shuts down immediately
Term
How long do you wait before turning the battery switch OFF after the APU selector is OFF? Why?
Definition
2 minutes
Allows a complete shutdown sequence with fire detection capability
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